Butterfly Life Cycle, Butterfly Metamorphosis, Egg, Larva, Pupa : Gardens With Wings Articles - Information About Butterflies, Caterpillars & Plants The Mysteries of Life November 2008 by Regina Cutter Edwards Butterflies go through four stages in life that are considered to be great mysteries. They are real survivors even with life’s many twists and turns. Butterflies have been able to adapt and make it through unimaginable obstacles. Butterflies are holometabolous, experiencing a complete metamorphosis, or in other words, a complete change in body form. They begin life as a larva and pupate into an immobile state and emerge as a butterfly, looking nothing like their pre-pupated state. Read on to learn more about these complicated yet fascinating stages of a butterfly’s life! Butterfly Egg The butterfly egg is spherical or ovate shaped, varying in color and size. It is covered by chorion, a hard shell that protects the egg, and is lined with a waxy layer that prevents dehydration. It is full of nutrients and is commonly the first meal for the newly hatched larva.

There is a small opening called a micropyle which allows sperm to enter the egg for fertilization while inside the female. To protect the egg and embryo that is forming, the eggs are attached to a leaf by the butterfly using an adhesive-like substance that glues the egg to the plant leaf. The nature of the “glue” is still fairly unknown in the scientific community. For protection, the eggs are often laid on the underneath side of the leaf so as not to be visible to predators. It is essential for the eggs to be laid on the host plant for that particular butterfly species. Eggs are sometimes laid in groups, although many butterflies such as the Monarch lay their eggs singly. The average time for the embryo to develop is 7-14 days but in instances where the egg is the overwintering stage, the embryo may take months to develop. Butterfly Larva (Caterpillar) The larva stage of the butterfly’s life cycle is a time for growth. The larva, also known as a caterpillar, spends its time eating and growing. The caterpillars feed on their host plants, which can range from a single species to many different species.

As caterpillars grow, they shed their exoskeleton. The exoskeleton is their support and protective structure outside their body. This process is called molting or ecdysis and is triggered primarily by hormones. The caterpillar forms a new cuticle underneath the old cuticle. Enzymes are secreted between the layers dissolving the muscle attachments to the old cuticle so the new cuticle can form without being exposed and the old cuticle can be shed. Each stage between molts is called an instar. Caterpillars usually have five instars before pupating, in which the same molting process occurs. Caterpillars have developed some interesting techniques to protect themselves. A common characteristic is camouflaging. Many caterpillars resemble plant parts, bird droppings, or may just look frightening to scare off predators. Many swallowtail caterpillars have huge ‘eye spots’ on their thorax regions and are able to inflate their body so that they appear snake-like. Swallowtail caterpillars also have an osmeterium, an interesting looking Y-shaped gland that protrudes out from above their head producing a smelly scent.

A few caterpillars are brightly colored and they usually are able to save plant toxin in their bodies, making them poisonous to predators. Or, they may mimic other poisonous caterpillars while being completely harmless. The same is true for caterpillars that are covered in body hairs - some have stinging body hairs to prevent getting eaten. As the caterpillar reaches the final instar, the wing pads have already begun developing. Right before the pupa stage the pads are forced out by the hemolymph, insect ‘blood,’ and by the time the larva has shed the exoskeleton to form the pupa, the wings are strongly attached to the body. This is why you can see the shape of the wings on the chrysalis. Pupa (Chrysalis) The pupa stage of the butterfly’s life cycle is a time for complete change. The pupa is also known as a chrysalis and is a vessel in which the slow moving caterpillar changes into a winged butterfly.

The process begins with the prothoracicotropic hormone (PTTH) triggering the caterpillar to quit eating and start wandering to a place to pupate, which is usually on twigs or other safe areas around their host plants but not necessarily on the host plants. Some butterfly species that over winter as a chrysalis may pupate in the leaf litter close to the ground. The chrysalis is immobile so it is important that it be camouflaged into the environment. For example, the Spicebush Swallowtail’s chrysalis takes on a brown or green color depending on the color of the environment. Many chrysalides are leaf shaped and vary in color from yellow, brown, green to silver and gold. Some chrysalides have the ability to wiggle and make a hissing sound in order to frighten predators. Butterflies go through a really amazing metamorphosis when being transformed from a caterpillar to an adult. The process inside the chrysalis is very intense. The insect’s body basically is liquefied by digestive fluids and the body is restructured using specialized formative cells. This process is called histogenesis, in which undifferentiated cells are used to build different body tissues.

This is similar to the building of tissues that can be done with stem cells in other animals. Adult Butterfly The adult stage of the butterfly’s life cycle is a time for reproduction. The adult is also known as an imago, they have fully developed wings and are sexually mature. When the adult first emerges from the chrysalis, their wings are wet and crinkled. They are able to pump fluid through their bodies into the wings to help them expand. Once their wings are fully expanded, they may take 30 minutes up to a couple hours to dry. They are then ready to fly. Many times right after the butterfly emerges from the chrysalis there will be a colored fluid that is released from the chrysalis, this is meconium, excess fluid the butterfly did not need. The adult butterfly’s primary instinctive behavior in life is to search for a mate of the same species and produce viable offspring to carry on their genes. This includes making sure the eggs are laid on the correct host plant. Some butterflies lay their eggs in groups, while others lay them singly because the first instar caterpillars can be cannibalistic and will eat the other eggs.

Predictability of Life Butterflies have been around for millions of years. They have evolved to withstand many obstacles they have encountered throughout the years, including predators and environmental occurrences. The dramatic differences in their life stages have given them the extra benefit of the larva and adult not having to compete with one another for resources, such as food. These mysteries to us have proven over time to be the predictable life for a butterfly. View an illustration of the life cycle of a Black Swallowtail as it transforms from egg to larva (caterpillar) to pupa (chrysalis) to adult. Photo Credits: Fred Miller and Diane P. Brooks References: Borror, D. J., Triplehorn C.A., Johnson, N.F. 1992. An Introduction to the Study of Insects (6th Ed). New York: Saunders College Publishing. Powell, J.A. 2003. Lepidoptera (Moths, Butterflies). Encyclopedia of insects. Ed. Vincent H. Resh, Ring T. Cardé. New York: Academic Press. p 631-664. Riddiford, L.M. 2003. Molting.

Encyclopedia of insects. Ed. Vincent H. Resh, Ring T. Cardé. New York: Academic Press. p 733-738. Enter your zip code: Pupa | Definition of Pupa by Merriam-Webster See words that rhyme with pupa Spanish Central: Translation of pupa Nglish: Translation of pupa for Spanish speakers Britannica English: Translation of pupa for Arabic speakers Britannica.com: Encyclopedia article about pupa Seen and Heard What made you want to look up pupa? Please tell us where you read or heard it (including the quote, if possible). Pupa | Define Pupa at Dictionary.com pupa [pyoo-pee] /ˈpyu pi/ (Show IPA), pupas. 1. an insect in the nonfeeding, usually immobile, transformation stage between the larva and the imago. Origin of pupa 1765-70; < New Latin, special use of Latin pūpa girl, doll, puppet.

See pupil 1, puppet Related forms Examples from the Web for pupa Expand Historical Examples Some Lepidopterous larv even (Alucita pentadactyla, Callimorpha rosea, &c.) assume the pupa state within their last skin. Our Common Insects Alpheus Spring Packard Next comes the pupa, armed for the exit even as the primary larva was equipped for entering. Our Common Insects Alpheus Spring Packard The species to which his principal attention was paid appears to have been the Locusta italica, in its larva and pupa state. Our Common Insects Alpheus Spring Packard Gasterotheca: that part of the pupa case that covers the abdomen. British Dictionary definitions for pupa Expand noun (pl) -pae (-piː), -pas 1. an insect at the immobile nonfeeding stage of development between larva and adult, when many internal changes occur See coarctate , exarate , obtect Derived Forms C19: via New Latin, from Latin: a doll, puppet Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd.

1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012 Word Origin and History for pupa Expand n. "post-larval stage of an insect," 1773, special use by Linnæus (1758) of Latin pupa "girl, doll, puppet" (see pupil (n.1)) on notion of "undeveloped creature." Related: Pupal; pupiform. Online Etymology Dictionary, © 2010 Douglas Harper Larva | Article about larva by The Free Dictionary Larva | Article about larva by The Free Dictionary Also found in: Dictionary , Thesaurus , Medical , Acronyms , Wikipedia . larva, independent, immature animal that undergoes a profound change, or metamorphosis, to assume the typical adult form. Larvae occur in almost all of the animal phyla; because most are tiny or microscopic, they are rarely seen. They play diverse roles in the lives of animals.

Motile larvae help to disseminate sessile, or sedentary, animals such as sponges sponge, common name for members of the aquatic animal phylum Porifera, and for the dried, processed skeletons of certain species used to hold water. Over 4,500 living species are known; they are found throughout the world, especially in shallow temperate waters. ..... Click the link for more information. , oysters oyster, bivalve mollusk found in beds in shallow, warm waters of all oceans. The shell is made up of two valves, the upper one flat and the lower convex, with variable outlines and a rough outer surface. ..... Click the link for more information. , barnacles barnacle, common name of the sedentary crustacean animals constituting the infraclass Cirripedia. Barnacles are exclusively marine and are quite unlike any other crustacean because of the permanently attached, or sessile, mode of existence for which they are highly modified. ..... Click the link for more information. , or scale insects.

Larvae of parasites may be dispersed by penetrating the skin of new hosts; other parasite larvae live in intermediate hosts that are normally eaten by the final host, in which the adult parasites develop. The larvae of other parasites live in and are dispersed by intermediate hosts such as mosquitoes mosquito , small, long-legged insect of the order Diptera, the true flies. The females of most species have piercing and sucking mouth parts and apparently they must feed at least once upon mammalian blood before their eggs can develop properly. ..... Click the link for more information. , gnats gnat, common name for any one of a number of small, fragile-looking two-winged flies of the suborder Nematocera, order Diptera, which includes the families Tipulidae (crane flies), Bibionidae (hairflies), Ceratopogonidae (biting midges), Chironomidae (true midges), Cecidomyidae ..... Click the link for more information. , or leeches leech, predacious or parasitic annelid worm of the class Hirudinea, characterized by a cylindrical or slightly flattened body with suckers at either end for attaching to prey. ..... Click the link for more information.

; when the blood meals are taken from the final host, the parasite larvae are introduced into the blood or skin. Parasitic infections can often be reduced by eliminating the larval hosts. Vertebrate Larvae Among vertebrates vertebrate, any animal having a backbone or spinal column. Verbrates can be traced back to the Silurian period. In the adults of nearly all forms the backbone consists of a series of vertebrae. All vertebrates belong to the subphylum Vertebrata of the phylum Chordata. ..... Click the link for more information. a number of fishes fish, limbless aquatic vertebrate animal with fins and internal gills. Traditionally the living fish have been divided into three class: the primitive jawless fishes, or Agnatha; the cartilaginous (sharklike) fishes, or Chondrichthyes; and the bony fishes, or Osteichthyes. ..... Click the link for more information. pass through larval stages; the larva of the eel eel, common name for any fish in the order Anguilliformes, and characterized by a long snakelike body covered with minute scales embedded in the skin.

Eels lack the hind pair of fins, adapting them for wriggling in the mud and through the crevices of reefs and rocky shores. ..... Click the link for more information. is interesting because it is flat and transparent. The tadpole, the familiar larva of the amphibian amphibian, in zoology, cold-blooded vertebrate animal of the class Amphibia. There are three living orders of amphibians: the frogs and toads (order Anura, or Salientia), the salamanders and newts (order Urodela, or Caudata), and the caecilians, or limbless amphibians (order ..... Click the link for more information. , develops to a considerable size in the relatively hospitable aquatic environment before metamorphosis prepares it for an amphibious or terrestrial life as a frog frog, common name for an amphibian of the order Anura. Frogs are found all over the world, except in Antarctica. They require moisture and usually live in quiet freshwater or in the woods. Some frogs are highly aquatic, while others are better adapted to terrestrial habitats. ..... Click the link for more information.

or toad toad, name applied to certain members of the amphibian order Anura, which also includes the frog. Although there is no clear-cut distinction between toads and frogs, the name toad ..... Click the link for more information. . Insect Larvae In some animals, especially insects insect, invertebrate animal of the class Insecta of the phylum Arthropoda. Like other arthropods, an insect has a hard outer covering, or exoskeleton, a segmented body, and jointed legs. Adult insects typically have wings and are the only flying invertebrates. ..... Click the link for more information. , larvae represent a special feeding stage in the life cycle. Some insects pass through more or less wormlike larval stages, enter the outwardly inactive, or pupal, form, and emerge from the pupal case as adults (see pupa pupa , name for the third stage in the life of an insect that undergoes complete metamorphosis, i.e., develops from the egg through the larva and the pupa stages to the adult. ..... Click the link for more information. ).

The importance of larvae in the life cycle of insects varies greatly, as does the proportion of the life span spent in larval, pupal, and adult stages. In many insects, the adult life is relatively short, consisting mostly of mating and egg laying, while the larvae live for many months or, in some species, for several years. Insect larvae feed voraciously, necessarily becoming larger than the adult, as considerable energy and material are needed for the profound changes made during pupation. For this reason, insect larvae often cause far more damage to stored crops and textiles than adult insects. Insect larvae generally have a thinner exoskeleton than the adult; many are white and soft. The characteristic fly fly, name commonly used for any of a variety of winged insects, but properly restricted to members of the order Diptera, the true flies, which includes the housefly, gnat, midge, mosquito, and tsetse fly. ..... Click the link for more information. larvae are maggots, often developing in decaying plant or animal material. Mosquito larvae are the familiar aquatic wrigglers; they breathe air and are killed by a thin film of oil on the water that prevents contact with air.

Maggots and wrigglers are legless, as are all larvae of the insect order Diptera. Beetle beetle, common name for insects of the order Coleoptera, which, with more than 300,000 described species, is the largest of the insect orders. Beetles have chewing mouthparts and well-developed antennae. ..... Click the link for more information. larvae, including the whitish forms called grubs and the long brownish wireworms wireworm, elongate, cylindrical larva of the click beetle. Most wireworms are hard and brown, but members of some species are soft and whitish. Wireworms live in rotten wood or in the ground and feed on roots and seeds, injuring potatoes, grasses, and a wide variety of ..... Click the link for more information. , are quite diverse, but all are equipped with the six legs characteristic of adults. Moths moth, any of the large and varied group of insects which, along with the butterflies, make up the order Lepidoptera.

The moths comprise the great majority of the 100,000 species of the order, and about 70 of its 80 families. ..... Click the link for more information. and butterflies butterfly, any of a large group of insects found throughout most of the world; with the moths, they comprise the order Lepidoptera. There are about 12 families of butterflies. Most adult moths and butterflies feed on nectar sucked from flowers. ..... Click the link for more information. have wormlike caterpillars as larvae, each equipped with the six legs characteristic of adults and false legs known as prolegs to support the long abdominal section. Some, like the milkweed worm (the larva of the monarch butterfly), are relatively naked, while other caterpillars are covered by hairy bristles, sometimes equipped with irritating chemicals that can cause intense itching. The young of the social insects ( bees bee, name for flying insects of the superfamily Apoidea, in the same order as the ants and the wasps. Bees are characterized by their enlarged hind feet, typically equipped with pollen baskets of stiff hairs for gathering pollen. ..... Click the link for more information.

, ants ant, any of the 2,500 insect species constituting the family Formicidae of the order Hymenoptera, to which the bee and the wasp also belong. Like most members of the order, ants have a "wasp waist," that is, the front part of the abdomen forms a narrow stalk, called the waist, ..... Click the link for more information. , wasps wasp, name applied to many winged insects of the order Hymenoptera, which also includes ants and bees. Most wasps are carnivorous, feeding on insects, grubs, or spiders. They have biting mouthparts, and the females have stings with which they paralyze their prey. ..... Click the link for more information. , and termites termite or white ant, common name for a soft-bodied social insect of the infraorder Isoptera. Originally classified in as a separate order, termites are genetically related to cockroaches and are now usually classified with them in the order Blattodea. ..... Click the link for more information. ) are legless but otherwise grublike.

Although all social-insect larvae are ultimately dependent on the parent colony for food, they are considered true larvae because they pass through a pupal stage. Larva a stage in the individual development of many invertebrates and some vertebrates (fishes and amphibians) in which the nutrient reserves of the egg are insufficient to complete embryonic development. An organism in the larval stage is self-sufficient. Usually it has special organs not characteristic of the adult form but lacks other organs characteristic of the adult. In many animals, the existence of the larval stage is determined by the differences in the modes of life of the early stages of development and that of the adult stage; thus, the trochophore, characteristic of polychaetes and many mollusks, is free-swimming, but the adult form is benthic. The presence of a larva is sometimes associated with a change in habitat in the course of development. For example, many amphibian larvae are adapted to aquatic life, whereas the adult animals are adapted to dry land. In sessile or sluggish marine animals, a free-swimming larva ensures offspring distribution.

This is true of the larvae of sponges and coelenterates (paren-chymula, amphiblastula, planula) and of echinoderms and enteropneusts (dipleurula). The metamorphosis of the larva to the adult animal consists in the restructuring of the larva’s organization; the more profound that restructuring, the greater will be the difference between the larva and the adult organism. The changes that occur in the metamorphosis of certain invertebrates (nemertines, echinoderms, and insects) are especially pronounced. For example, in higher insects in the pupal stage (which follows the larval stage), almost all of the larval organs are destroyed. The organs of the adult animal are formed de novo from special rudiments called imaginal disks. The larvae of some animals retain the structural characteristics of ancestral forms. For example, phylogenetic significance of this sort is ascribed to the larvae of sponges and coelenterates (parenchymula, planula) and to the caudate larvae of ascidians, which resemble a free-swimming ancestor in structure. A. V.

I Butterfly Pictures Butterfly Pictures Copyright � 2009 JungleWalk.com and its licensors. You can customize this image and buy at it as a Poster | T-Shirt | Magnet | Tote Bag | Mousepad More About Butterflies ... A butterfly is a flying insect of the order Lepidoptera belonging to one of the superfamilies Hesperioidea (the skippers) and Papilionoidea (all other butterflies). Many butterflies have striking colours and patterns on their wings. People who study or collect butterflies (or the closely- related moths) are called lepidopterists Unlike many insects, butterflies do not experience a nymph period, but instead go through a pupal stage which lies between the larva and the adult stage (the imago). Egg Larva, known as a caterpillar Pupa (chrysalis) Adult butterfly (imago) Butterfly eggs consist of a hard-ridged outer layer of shell, called the chorion. This is lined with a thin coating of wax which prevents the egg from drying out before the larva has had time to fully develop.

Each egg contains a number of tiny funnel-shaped openings at one end, called micropyles; the purpose of these holes is to allow sperm to enter and fertilize the egg. Butterfly and moth eggs vary greatly in size between species, but they are all either spherical or ovate. Larvae, or caterpillars, are multi-legged eating machines. They consume plant leaves and spend practically all of their time in search of food. As they mature their skin is shed several times. When the larva has eaten enough it will will form a chrysalis (Butterflies do not spin cocoons, moths do.) The larva usually moves to the underside of a leaf. To form a cocoon it spins a silk-like thread around itself. A chrysalis is formed by hardening bodily secretions. A larva completely covered by a cocoon or chrysalis is called a pupa. Inside its protective shell the larva will transform into a butterfly (or moth), a process known as metamorphosis. The adult, sexually mature, stage of the insect is known as the imago.

As Lepidoptera, butterflies have four wings, but unlike moths, the fore and hindwings are not hooked together, permitting a more graceful flight. A butterfly has six legs; the larva also has six true legs and a number of prolegs. After it emerges from its pupal stage it cannot fly for some time because its wings have not yet unfolded. A newly emerged butterfly needs to spend some time 'inflating' its wings with blood and letting them dry, during which time it is extremely vulnerable to predators. Many species of butterfly are sexually dimorphic. Some butterflies, such as the Monarch butterfly, are migratory. Butterflies are often confused with moths, but there are a few simple differences between them, including colour, habits, and pupating appearance. See the difference between a butterfly and a moth. Butterflies live primarily on nectar from flowers. Some also derive nourishment from pollen, tree sap, rotting fruit, dung, and dissolved minerals in wet sand or dirt. Butterflies are also pollinators. Aquatic Insect Metamorphic Life Stages Depending on insect order, aquatic insects undergo either incomplete or complete metamorphosis.

Incomplete The life stages of insects undergoing incomplete metamorphosis are egg, nymph, and adult. The initial (egg) life stage begins when an adult female oviposits eggs. The egg generally finds its way to the bottom of a body of water, either by gravity or actual placement, where it becomes attached to the substrate and begins a period of growth and development. The length of this period is generally 1-2 weeks. The 2nd (nymphal) life stage begins when the immature nymph escapes its egg, and begins actively feeding and growing. Having the limitation of an external skeleton, which won't accommodate much growth, this exoskeleton must be periodically shed, and another larger one formed. This process is called molting. The period between molts is called an instar. The number of nymphal instars can vary from 8 to 30 (or more) for different insect orders. The nymphal period can vary from several months to as long as 2 or 3 years for some large aquatic insects. The 3rd (adult) life stage commences with a mature larva transforming into a winged adult form.

The exception to this is mayflies, which first transform into a winged (sexually-immature) adult form called a dun (subimago), and shortly thereafter transform into a winged (sexually-mature) adult form called a spinner (imago). Among aquatic insects sharing incomplete metamorphosis are mayflies , damselflies , dragonflies , stoneflies , and waterbugs . Complete Metamorphosis The life stages of insects undergoing complete metamorphosis are egg, larva, pupa, and adult. The initial (egg) life stage is the same as described above under incomplete metamorphosis. The 2nd (larval) life stage begins when the immature larva escapes its egg, and begins actively feeding and growing. Larvae undergo the same molting process as described for nymphs. The number of larval instars can vary from 3 to 11 for different insect orders. The nymphal period is a short as a single week for some true fly families, but is as long as a year or more for others .The larva pictured here is of a chironomid, a type of true fly, which doesnt have an obvious head or jointed legs, and looks rather worm-like.

However, larvae of most orders (of aquatic insects undergoing complete metamorphosis) do have an obvious head and jointed legs, therefore don't look nearly so worm-like. The 3rd (pupal) life stage begins when the mature larva transforms into a pupa. A terrestrial insect example of pupation is the caterpillar, which seals itself in a cocoon to pupate prior to emerging as a butterfly. The 4th (adult) life stage begins when the pupa undergoes metamorphosis and transforms into a winged adult. Insects: pictures, information, classification and more Microsoft Illustration Nervous System The nervous system of an insect centers around a nerve cord that runs from the head to the abdomen along the underside of the body. Typically the cord is equipped with a pair of ganglia, or nerve centers, for each segment of the body. The brain, which is located just above the gullet, is made up of three ganglia fused into one. The brain receives stimuli from the antennae and from the eyes. The sense organs of insects consist of eyes, auditory organs, organs of touch, organs of smell, and organs of taste. Insect eyes are of two types, compound and simple.

Each of the two compound eyes, which are usually situated directly behind the antennae, contains from 6 to 28,000 or more light-sensitive structures, called ommatidia, grouped under a lens or cornea that is composed of an equal number of hexagonal prism-shaped facets. These structures permit only light that is parallel to their axes to reach the nerve endings, and thus they build up an optical image that is a mosaic of the light impulses reaching the individual nerves. Many species have in addition simple eyes, or ocelli, that are usually located between the compound eyes. Entomologists believe that the compound eyes are adapted to seeing swiftly moving objects, whereas the simple eyes are adapted to seeing nearby objects and fluctuations in light intensity. Each ocellus has a simple lens overlying a series of light-sensitive nerve elements, all of which are connected by a single nerve to the brain. The auditory organs of insects vary widely in structure and in some species are quite complex. In some grasshoppers, large auditory membranes are situated on either side of the first segment of the abdomen. Behind these membranes are fluid-filled spaces that transmit the sound impulses to nerve endings that project into the fluid.

Other types of grasshoppers and crickets have auditory organs on their legs below the knee joints. These organs consist of membranes with air chambers beneath them that communicate with the outside air through slits in their walls and are supplied with nerve endings. The organs of touch in insects resemble hairs and are located on various parts of the body and on the antennae. Microsoft Illustration Reproduction The various species of insects exhibit extreme variety in their modes of reproduction. In some insects, such as the honey bee, the reproductive female, or queen, produces thousands of fertilized eggs over a period of several years, although the male, or drone, dies shortly after mating. In other species, such as the mayflies, both male and female insects have only a short span of life after mating. In a number of species of beetles, both males and females mate repeatedly. In addition, various species of insects reproduce parthenogenetically, developing from unfertilized eggs. This form of reproduction occurs regularly in certain species, and occasionally or in alternate generations in others. In some gall wasps and sawflies, all reproduction is apparently by parthenogenesis, and no sexual reproduction is known.

In the social bees and other related insects, male insects are produced from unfertilized eggs. In certain moths, which exhibit sporadic parthenogenesis, both sexes may be produced from unfertilized eggs. Among the aphids several successive generations of females may be produced parthenogenetically before the production of a generation of male and female insects that reproduces sexually. Photo by: J.A.L. Cooke/Oxford Scientific Films Certain flies occasionally reproduce by means of paedogenesis: the production of eggs by immature forms, either larvae or pupae. The larvae of some midges produce several generations of larval females before producing male and female larvae that develop into adult insects and reproduce sexually. The method of development of eggs also varies widely among the insects. Some insects are viviparous, giving birth to living young. In other species, the entire larval stage of development takes place within the body of the female, and the insect becomes a pupa at birth. Most insect eggs, however, are deposited and hatch outside the body of the parent. The egg-laying habits of the different species vary. Many insects deposit single eggs or masses of eggs on the plants on which the larvae will feed.

A number of insects lay their eggs within the tissues of the food plant, and the eggs may give rise to swellings, or galls, on the leaves or stems of the plant. Certain insects show a unique form of embryonic development in which more than one embryo is formed by a single egg. This process is known as polyembryony, and in some species more than 100 larvae are formed from a single egg by division within the egg. Microsoft Illustration Metamorphosis One of the characteristics of the development of insects from birth to maturity is metamorphosis, the change through one or more distinctive immature body forms to the imago, or adult body form. Metamorphosis of some kind occurs in most insects, although in a few species, such as the bristletails, the newborn insect is essentially similar in form to the imago. Entomologists recognize two basic forms of metamorphosis: complete and incomplete. In complete metamorphosis, the insect first assumes a larval form, an active immature form typified by the caterpillar; then changes to a pupa, a more or less dormant form, often enclosed in a cocoon; and finally emerges as the adult insect, or imago.

A form of complete metamorphosis in which the insect larva undergoes one or more changes in form (usually to adapt it to a change in food supply) before becoming a pupa is called hypermetamorphosis. Hypermetamorphosis takes place in certain beetles and flies and certain parasitic insects of the order Hymenoptera. In incomplete metamorphosis, the insect is born in a relatively mature form called a nymph, which resembles the imago but lacks or has only partly developed wings and reproductive apparatus. The nymph changes to the imago by a gradual process, and no pupal stage occurs. The nymphal stages are separated by molting, or ecdysis, of the inelastic exoskeleton, each successive stage being more like the adult. In the simplest insects, the changes between successive nymphal stages are slight, but generally the stages are distinctly different. In a typical example of complete metamorphosis, the larva is a caterpillar that can crawl in search of food and that has mouth parts adapted for feeding on leaves or grasses. As the larva grows, it sheds its skin from three to nine times.

At the end of the larval period, the insect spins a cocoon about itself or, in the case of most cutworms and certain other insects, forms an underground earthen cell and enters the pupal stage. During the pupal stage the insect is quiescent and does not eat, but its body gradually assumes the imago form. At this time the wings and other body structures of the mature insect begin to develop. When the pupa is fully developed, it breaks out of its cocoon or earthen cell and pupal exoskeleton and emerges as a complete adult insect, such as a moth or butterfly. Photo by: L. West/Photo Researchers, Inc. Insect Attractant Attractants are the visual, auditory, or chemical means by which male insects are attracted to females, and vice versa. Some insects, such as butterflies, attract members of the opposite sex by visual means; crickets, grasshoppers, and related insects use sound. In many insect species the females release small quantities of powerful chemical substances called pheromones that attract the males.

Female saturniid and lasiocampid moths are reported to have lured males from 4 km (2.5 mi) away, and in one experiment a caged female pine sawfly attracted more than 11,000 males. In one method of insect pest control the attractant, generally a different chemical for each species of insect, is extracted from the females; or, if its structure is known, it is synthesized. Photo by: Dorling Kindersley The chemical is used to lure thousands of males of that species into contact with an insecticide and annihilation. Fossil Insects The earliest known fossil insects have been found in Devonian rocks and represent forms of wingless insects that lived more than 400 million years ago. The fossil records indicate that the class may have developed in a still earlier period. Scientific classification: The class of insects is arranged in various ways by different entomologists; the following classification is representative. The whole class Insecta is divided into two subclasses: the Apterygota, wingless insects; and the Pterygota, including the great bulk of insects, most of which have wings in the imago form.

The Apterygota are divided into four orders: the Protura, a group of very tiny, blind insects; the Thysanura, which includes the silverfish; the Diplura, a small group that contains the largest (about 5 cm/2 in long) of the Apterygota, an insect of the genus Heterojapyx; and the Collembola, which includes the springtail.

The Pterygota are divided into 27 orders: the Ephemeroptera, which includes the mayflies; the Plecoptera, the stone flies; the Odonata, the dragonflies and damselflies; the Grylloblattodea, a small wingless order; the Orthoptera, the katydids, crickets, and grasshoppers (locusts); the Phasmida, the walkingsticks; the Thysanoptera, the thrips; the Dermaptera, the earwigs; the Mantodea, the mantids; the Blattaria, the roaches (sometimes placed together with the mantids in the order Dictyoptera); the Isoptera, the termites; the Embioptera, a small group of subsocial insects living in tropical and subtropical regions; the Psocoptera, the bark lice and book lice; the Phthiraptera, the bird lice and true lice (sometimes separated into the two orders Mallophaga and Siphonculata); the Zoraptera, of which only one termitelike genus (including about 20 species) is known; the Megalopt

era, the alderflies and dobsonflies; the Raphidiodea, the snake flies; the Neuroptera, the antlions and lacewings; the Mecoptera, the scorpion flies; the Trichoptera, the caddisflies; the Lepidoptera, the butterflies and moths; the Diptera, the mosquitoes, gnats, and true flies; the Siphonaptera, the fleas; the Coleoptera, the beetles; the Strepsiptera, a group of tiny insects parasitic on other insects; the Hymenoptera, including the ants, bees, wasps, hornets, and ichneumons, and chalcids; and the Hemiptera.

Share this page with your friends! pupa, pupae, pupate, pupation - BugGuide.Net pupa, pupae, pupate, pupation No Taxon pupa, pupae, pupate, pupation Explanation of Names Latin, pupa, a puppet, original meaning apparently "a young girl". Identification pupa noun, plural pupae or pupas - in holometabolous insects (those showing complete metamorphosis ), the third life stage. A pupa is normally not able to move (though some flex in place) and does not feed. This is the transformative stage between larva and imago (adult). The verb pupate means to form a pupa, and the process is called pupation. Some examples of pupae: Gordh, A Dictionary of Entomology, p. 755 ( 1 ) Internet References George Gordh, David H. Headrick. 2003. CABI Publishing.

Contributed by Cotinis on 24 May, 2007 - 8:22pm Additional contributions by Beatriz Moisset , Chuck Entz Last updated 21 April, 2011 - 3:15pm Disclaimer: Dedicated naturalists volunteer their time and resources here to provide this service. We strive to provide accurate information, but we are mostly just amateurs attempting to make sense of a diverse natural world. If you need expert professional advice, contact your local extension office . Contributors own the copyright to and are solely responsible for contributed content. Click the contributor's name for licensing and usage information. Everything else copyright © 2003-2017 Iowa State University, unless otherwise noted. Bugguide is hosted by:

Question: The state in some insects between the larva and the imago is known as what?
Answer: PUPA